Shorter Rules Are Better, Aren't They?

It is conventional wisdom in inductive rule learning that shorter rules should be preferred over longer rules, a principle also known as Occam’s Razor. This is typically justified with the fact that longer rules tend to be more specific and are therefore also more likely to overfit the data. In this position paper, we would like to challenge this assumption by demonstrating that variants of conventional rule learning heuristics, so-called inverted heuristics, learn longer rules that are not more specific than the shorter rules learned by conventional heuristics. Moreover, we will argue with some examples that such longer rules may in many cases be more understandable than shorter rules, again contradicting a widely held view. This is not only relevant for subgroup discovery but also for related concepts like characteristic rules, formal concept analysis, or closed itemsets.